Reds are 16+, and the player is very good to world class at those attributes. greens are 11-15 I think and the player is adequate to fairly good at those attributes (for top level football). When I'm scouting, I can quickly tally up the number or reds a player has to determine his quality. I think in the default color scheme the colors of the numbers match up to the colors of the polygon, which is another good way to measure a player. I just prefer having less colors.